Fluorimetric Assay for the Determination of Glutamic Acid Decarboxylase Activity in Subregions of Rat Brain Tissue

Abstract
A modification of the spectrofluorimetric method of Lowe et al. for the measurement of glutamic acid decarboxylase (GAD) activity in rat brain is described. This method involves the indirect determination of GAD activity by measurement of the formation of GABA. The minimum activity of GAD observable was 0.45 .mu.g GABA/h per mg protein and the limit of detection was 0.20 .times. 10-6 M GABA. This method was developed for measurement of GAD activity of gabaergic terminals in globus pallidus, endopeduncular nucleus, substantia nigra, and ventromedial thalamus in rat brain.